In medium pot, heat water for pasta. Add 1 T of the salt to water. Once boiling, add pasta and cook according to package. Once pasta is done, strain and set aside. Note: While pasta is cooking, turn on broiler.
Meanwhile, in a large pot, heat butter on medium heat. Once melted, add flour, mustard powder, and the remaining ½ T salt. Whisk together until well combined (this is your roux). Slowly, add cold milk to the roux. Turn heat to high. Whisk mixture frequently until lumps go away. Then stir constantly for 5ish minutes, until you sauce is as thick as you'd like. Add 2 ½ cups of the cheese and cook until cheese is melted.
Cook broccoli in microwave according to package. Add pasta, cooked broccoli and ham to cheese sauce. Mix together.
Pour mixture into 8x10 casserole dish. Sprinkle casserole with bread crumbs and the remaining ½ cup of the cheese. Put dish on top rack of oven and broil for 4 minutes.
Scoop macaroni and cheese into bowls or plates. Serve alone or with a side, like cherry tomatoes and sliced cucumbers, or a salad.We recommend that all meals for children be served with milk.